The Evolution of Vaccines: From Smallpox to COVID-19
Vaccines have been a part of modern medicine since their invention over 300 years ago. As science and technology evolve, so too has the development of vaccines. This article will explore the rich and varied history of vaccines, from early inoculation in the 1700s to the current work being done to develop a vaccine for COVID-19.
A Brief History of Vaccines
Vaccines have a long and storied history, dating back to 1796 when Edward Jenner developed a vaccine for smallpox. Jenner’s innovation of exposing a patient to the less severe cowpox virus effectively provided protection against the more severe smallpox infection. This marked the dawn of modern vaccine science.
As the 19th century progressed, more infectious diseases became understood, and more effective vaccines to prevent them were developed. In 1885, Louis Pasteur developed a weakened form of the chicken pox virus and by 1897, the first diptheria vaccine was available. In the 20th century, numerous vaccines were developed further in hopes of creating protection against several viral and bacterial illnesses ranging from Scarlet fever, to polio, to mumps.
The Rise of Synthetic Vaccines
In the early 21st century, the advent of synthetic gene technology made it possible for scientists to create vaccines for a variety of illnesses. Synthetic vaccines are constructed from bits of genes, proteins, or peptides from the microbe or virus in question. Synthetic vaccines are considered to be better than live vaccines or traditional vaccines because they stimulate the body to create an immune response without introducing any pathogens into the body. Synthetic vaccines can also be created easily, quickly and cost efficiently, making them especially useful for rapidly developing responses to emerging and re-emerging global infectious diseases.
From Smallpox to COVID-19
Initially beginning with smallpox, vaccines have come a long way in protecting individuals and populations from a wide range of illnesses. Vaccines have been developed not only to treat existing communicable diseases, but also to prevent them, an especially potent weapon in managing the global pandemic of COVID-19.
The Race for a Vaccine
In the wake of COVID-19’s emergence in early 2020, the world has raced to develop a vaccine. Work to develop this vaccine has leveraged both existing and novel technology. More than 100 countries are working on COVID-19 vaccine research and development, with more than 150 total vaccine candidates in the works. Twenty-eight vaccine candidates are in Phase 1 or Phase 2 clinical trials, with eleven of those in Phase 3 trials.
Vaccine Types
Of the 28 candidates in clinical trials, the vaccine types vary, including both synthetically created vaccines and mRNA vaccines. mRNA vaccines are a relatively new technology that uses genetic material instead of weakened or killed virus to stimulate the body’s immune response. For example, the Pfizer vaccine is an mRNA vaccine which was the first to be approved in the US in 2020. In total, the world has now approved nine COVID-19 vaccines, five of which are synthetic vaccines and four which utilize mRNA technology.
Challenges
While rapid developments and technological breakthroughs have spurred the speed with which COVID-19 vaccines were developed and produced, several unique challenges remain. Aside from logistical challenges posed by the delivery of vaccines on a global scale, there is also the challenge of communicating logistical, technical and ethical requirements to populations that may not be familiar with issues normally encountered in vaccine development and production.
In addition, vaccine hesitancy remains a challenge in some communities and poses a further challenge to the widespread application and acceptance of the vaccines. For vaccine acceptance to occur, there must be a trust that the vaccine is both safe and effective, so comprehensive and effective community-level communication is an integral part of achieving global vaccine access.
Vaccines have come an incredibly long way since Edward Jenner’s breakthrough inoculation for smallpox over 200 years ago. In 2020, we have seen the development of COVID-19 vaccines at an unprecedented speed, thanks to a combination of novel technologies and global collaboration. The challenge of producing and efficiently delivering the vaccines to populations around the world remains the number one priority for global health organizations. If a successful global distribution of the vaccine can be achieved, it is hoped that the long-term human and economic suffering caused by the pandemic will end.
